“…Peroxiredoxins, a large antioxidant gene family, have a wide tissue distribution but the highest expression of Prx I and Prx II occur in bone marrow, liver, testis, ovary and heart, followed by spleen and brain [13,15]. Using immunohistochemical staining of mouse pancreas we show that Prx I and Prx II expression is mainly localized to pancreatic islets, with almost no signals in exocrine pancreas.…”
Section: Discussionmentioning
confidence: 82%
“…Mouse insulinoma cells βTC6-F7 (passages [15][16][17][18][19][20] were propagated in DMEM medium containing 5.5 mmol/l glucose, supplemented with 10% heat-inactivated FCS, 100 U/ml penicillin and 100 µg/ml streptomycin. Rat insulinoma cells INS-1 (passages [13][14][15][16][17][18][19][20] were propagated in RPMI-1640 medium containing 11 mmol/l glucose, supplemented with 10% heat-inactivated FCS, 100 U/ml penicillin, 100 µg/ml streptomycin, 10 mmol/l HEPES-buffer, 2 mmol/l L-glutamine, 1 mmol/l sodium pyruvate, 50 µmol/l β-mercaptoethanol. All cells were cultured at 37°C in a humidified atmosphere containing 95% air and 5% CO 2 .…”
Aims/hypothesis. Insulin-producing beta cells are destroyed by oxidative and nitrosative stress during the pathogenesis of Type I (insulin-dependent) diabetes mellitus. These cells are more sensitive than others due to their deficiency of well known antioxidant enzymes like superoxide dismutase, glutathione peroxidase and catalase. However the peroxiredoxins discovered in the past decade form a large family of highly conserved thioredoxin-dependent peroxide reductases, which are present in most tissues. We investigated whether peroxiredoxins I and II are present in pancreatic beta cells and if they are inducible by oxidative and nitrosative stress. Methods. To detect these enzymes in insulin-producing beta cells we used semiquantitative RT-PCR, western blots and immunohistochemistry. The expression of peroxiredoxins I and II was analysed after treatment with cytokines, hydrogen peroxide, alloxan or streptozotocin in the rat insulinoma cells INS-1 using RT-PCR and western blots. Results. We show that peroxiredoxins I and II are present in the cytoplasm of pancreatic islet cells as well as in insulinoma cell lines βTC6-F7 and INS-1. Peroxiredoxins I and II were up-regulated by all stress agents used. Conclusion/interpretation. Beta cells, undersupplied with well characterized antioxidant enzymes, possess an additional antioxidant system which is inducible by oxidative as well as nitrosative stress. [Diabetologia (2002) 45:867-876]
“…Peroxiredoxins, a large antioxidant gene family, have a wide tissue distribution but the highest expression of Prx I and Prx II occur in bone marrow, liver, testis, ovary and heart, followed by spleen and brain [13,15]. Using immunohistochemical staining of mouse pancreas we show that Prx I and Prx II expression is mainly localized to pancreatic islets, with almost no signals in exocrine pancreas.…”
Section: Discussionmentioning
confidence: 82%
“…Mouse insulinoma cells βTC6-F7 (passages [15][16][17][18][19][20] were propagated in DMEM medium containing 5.5 mmol/l glucose, supplemented with 10% heat-inactivated FCS, 100 U/ml penicillin and 100 µg/ml streptomycin. Rat insulinoma cells INS-1 (passages [13][14][15][16][17][18][19][20] were propagated in RPMI-1640 medium containing 11 mmol/l glucose, supplemented with 10% heat-inactivated FCS, 100 U/ml penicillin, 100 µg/ml streptomycin, 10 mmol/l HEPES-buffer, 2 mmol/l L-glutamine, 1 mmol/l sodium pyruvate, 50 µmol/l β-mercaptoethanol. All cells were cultured at 37°C in a humidified atmosphere containing 95% air and 5% CO 2 .…”
Aims/hypothesis. Insulin-producing beta cells are destroyed by oxidative and nitrosative stress during the pathogenesis of Type I (insulin-dependent) diabetes mellitus. These cells are more sensitive than others due to their deficiency of well known antioxidant enzymes like superoxide dismutase, glutathione peroxidase and catalase. However the peroxiredoxins discovered in the past decade form a large family of highly conserved thioredoxin-dependent peroxide reductases, which are present in most tissues. We investigated whether peroxiredoxins I and II are present in pancreatic beta cells and if they are inducible by oxidative and nitrosative stress. Methods. To detect these enzymes in insulin-producing beta cells we used semiquantitative RT-PCR, western blots and immunohistochemistry. The expression of peroxiredoxins I and II was analysed after treatment with cytokines, hydrogen peroxide, alloxan or streptozotocin in the rat insulinoma cells INS-1 using RT-PCR and western blots. Results. We show that peroxiredoxins I and II are present in the cytoplasm of pancreatic islet cells as well as in insulinoma cell lines βTC6-F7 and INS-1. Peroxiredoxins I and II were up-regulated by all stress agents used. Conclusion/interpretation. Beta cells, undersupplied with well characterized antioxidant enzymes, possess an additional antioxidant system which is inducible by oxidative as well as nitrosative stress. [Diabetologia (2002) 45:867-876]
“…In addition, levels of peroxiredoxin (Prx) 1 and 2 in the livers of young (6–7 months old) Tg( TXN ) +/0 and WT control mice were measured because one of the major roles of Trx is as a hydrogen donor for Prxs in reductive reactions, which reduce peroxides [3,4]. The data in Figure 10 show that no significant changes in Prx1 (Figure 10(a)) and Prx2 (Figure 10(b)) levels were observed in the livers of young (6–7 months old) Tg( TXN ) +/0 and WT control mice.10.1080/20010001.2018.1533754-F0010Figure 10. Levels of Prx 1 and Prx 2 in Tg( TXN ) +/0 and WT mice.…”
Section: Resultsmentioning
confidence: 99%
“…Trx1 plays an important role in maintaining the reduced environment in cells through thiol-disulfide exchange reactions. A major role of Trx is as a hydrogen donor for enzymes involved in reductive reactions, e.g., ribonucleotide reductase, which reduces ribonucleotides to deoxyribonucleotides for DNA synthesis; peroxiredoxins (Prxs) which reduce peroxides [3,4]; and methionine sulfoxide reductases, which reduce methionine sulfoxide in proteins and provide protection against oxidative stress [6–8]. All Trxs catalyze the reduction of disulfides in proteins more efficiently (orders of magnitude faster) than GSH or dithiothreitol [9].…”
Section: Discussionmentioning
confidence: 99%
“…Both Trx1 and 2 play essential biological roles in mammals. Some of the physiologically important roles of Trx include: 1) acting as a hydrogen donor for enzymes involved in reductive reactions [3–8]; 2) maintaining a reduced environment in cells [9]; 3) controlling protein (especially transcription factors) function via the redox state [10–12] and the expression of target genes; 4) protecting cells and tissues from oxidative stress [13]; and 5) having anti-apoptotic effects through the inhibition of the ASK [14] and mitochondrial pathways [15]. The essential biological roles of Trx were further supported by two studies which demonstrated that mice null for either Trx1 or Trx2 were embryonically lethal [16,17].…”
We examined the effects of continuous overexpression of thioredoxin (Trx) 1 on aging in Trx1 transgenic mice [Tg(TXN)+/0]. This study was conducted to test whether increased thioredoxin expression over the lifespan in mice would alter aging and age-related pathology because our previous study demonstrated that Tg(act-TXN)+/0 mice had no significant maximum life extension, possibly due to the use of actin as a promoter, which may have resulted in loss of Trx1 overexpression during aging. To test this hypothesis, we generated new Trx1 transgenic mice using a fragment of the human genome containing the TXN gene with an endogenous promoter to ensure continuous overexpression of Trx1 throughout the lifespan. Universal overexpression of Trx1 was observed, and Trx1 overexpression was maintained during aging (up to 22–24 months old) in the Tg(TXN)+/0 mice. The levels of Trx1 are significantly higher (approximately 4 to 31 fold) in all of the tissues examined in the Tg(TXN)+/0 mice compared to the wild-type (WT) littermates. The overexpression of Trx1 did not cause any changes in the levels of Trx2, glutaredoxin, glutathione, or other major antioxidant enzymes. The survival study demonstrated that male Tg(TXN)+/0 mice slightly extended the earlier part of the lifespan compared to WT littermates, but no significant life extension was observed over the lifespan. The cross-sectional pathological analysis (22–25 months old) showed that Tg(TXN)+/0 mice had a significantly higher severity of lymphoma and more tumor burden than WT mice, which was associated with the suppression of the apoptosis signal-regulating kinase 1 (ASK1) pathway. Our findings suggest that the increased levels of Trx1 over the lifespan in Tg(TXN)+/0 mice showed some beneficial effects (slight extension of lifespan) in the earlier part of life but had no significant effects on median or maximum lifespans, and increased Trx1 levels enhanced tumor development in old mice.
Easy as π: An unusual indenylidene to η5‐indenyl rearrangement of a ruthenium catalyst has been observed. The resulting complex is the formal decomposition product of an olefin metathesis precatalyst that displays exceptional activity in the racemization of chiral alcohols at very low catalyst loadings.
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